Argument47【0806G desperado小组】第5次作业by 铅华落尽

hdofrucUID: 2434623

1、  没有足够证据证明除了彗星撞击和火山喷发没有其他方式会造成大片尘埃云层，可能是其他科学家未发现的原因，而且太阳本身也有变化，不能保证不会是太阳本身变暗了，比如太阳内原子裂变受阻
2、  数据记录只有欧洲和亚洲，导致没有足够的证据表明彗星撞击不可能，因为闪光可能不被记录，如撞击地点是尚无较成熟文明的地区（大洋洲，南极洲之类的），
3、  亚洲记录的巨声不一定是火山爆发，小行星撞击、巨大的地震也会产生巨响；而且即使是火山爆发，也没有足够的证据证明火山爆发能够造成大范围的气候变冷；即使火山爆发能造成气候变冷也不能肯定就没有其他因素




TOPIC: ARGUMENT47 - Scientists studying historical weather patterns have discovered that in the mid-sixth century, Earth suddenly became significantly cooler. Although few historical records survive from that time, some accounts found both in Asia and Europe mention a dimming of the sun and extremely cold temperatures. Either a huge volcanic eruption or a large meteorite colliding with Earth could have created a large dust cloud throughout Earth's atmosphere that would have been capable of blocking enough sunlight to lower global temperatures significantly. A large meteorite collision, however, would probably create a sudden bright flash of light, and no extant historical records of the time mention such a flash. Some surviving Asian historical records of the time, however, mention a loud boom that would be consistent with a volcanic eruption. Therefore, the cooling was probably caused by a volcanic eruption.
WORDS: 349          TIME: 00:44:23          DATE: 2007-12-15 21:34:44

This argument presents some possible reasons of a suddenly cooler period in the mid-sixth century, and claims that the cooling was probably caused by a volcanic eruption. However, I found so many indeterminations and suspicions against the author's assumptions and evidence, therefore it is not convincing enough.

Firstly, there are no enough prove which can conclude that no other causes to form the large dust cloud assumed exist. The author does not give enough evidence that it was a large dust that cause the cooling, and even presume it was right, there could be other reasons which can make the dust cloud, such reasons might not be discovered by scientist. In addition, the sun itself might change inside, which can cause a dimming effect If this happened, none of the reasons the author give is necessary.

Secondly, the recorder this argument relies on only includes Europe and Asia, which means that if there did happened a large meteorite colliding, which might cause the cooling too, it might not be recorded by any history, especially if the colliding occured at a place no civilization in existence. Such places might be Antarctica or Oceania, and etc. And what if the flash was not obvious enough or took place at a raining day? In both cases, the flash might not be written down as people might think of it as a lightning because of the weather.

Thirdly, the recorder of the loud boom, which the author refers to, is not definitely a symbol of volcanic eruption, as small planet crash or even huge earthquake could make such a loud boom. Even this assumption is credible, we can still not tell that a volcanical eruption could cause the cooling, short of information to prove that. And still, there might be other origins of the cooling.

To sum up, this argument relies on a series of unproved evidences and unilateral recorders, and ignores many other probably causes might result in the cooling. Therefore, it is not persuasive enough to make me believe it. If the author provides more information about the issues I mentioned before, it will be much reliable.